Abrasive machine



July'31, 1945.- n. PRQNpvosT ASIVE MACHINE Filed Aug. 5,v 194s MWL n l 4 f77/far@ work is attached a vpush handle 4,

-. Patented July 3 1, 1945 AUNITED. STATES 'PATENT OFFICE;

assesse- ABBASIYE MACHINE David Prono'vost, Rosemont, Mon-real, Quebec Canada i application um s, 194s, serial No. 497.411 Y .comma (orsi- 175i The present invention pertains to a novel portable abrasive machine and resides in improvements on the apparatus shown in my U. S. Patent No. 2,289,932 of July 14.` 1942.

The main object of the invention is to provide a machine having a pair of abrasive heads that s et up equal and opposite reactive forces at any given instant of operation, so that theoperator is not required to push the machine -against themachine frame, with its stroke adjusted accordingly.. Y

Another operating on a floor, to work close to the walls. With this object in view,the overall width of the abrading heads is made somewhat greater than that of the machine frame and symmetrical therewith.

Theinvention is fully disclosed by way of ex lll ing arm I1, and the forward ends of these arms carry weighted heads I8 resting on the floor I8. The heads have convex surfaces facing ,downward and covered with a suitable abrasive 2l.

Such abrasive may be sandpaper or, in some cases, closely packed metal teeth, or 7carbonate stone according to requirements.

In the operation of the device, the heads are always moving opposltely to one another because of their 180 spacing around the finalL driven shaft I I. Thus, their reactive forces balance each other, and the operaton is not required to push againststhe reaction of either head.

VIn'the construction shown in Figures 1, 2 and 3, each head is approximately half the width of the framework I and posltlonedfso that it 'passes object is to enable the machine, while the other when the bearings IB are in vertical alinement. The arm I in each case is attached to the center of the head and is bent outward at 22 towards the corresponding bearing. Uprights 23 extending from the frame ll guide arms I1.

ample in the following description and in the ac- 4 `companying drawing in which:

Figure `1 is a side elevation of the machine; Figure 2 is a front elevation: Figure 3 is a fragmentary plan view, and Figure 4 is a similar planview; of a modification.

Reference to these vviews will now be made lby use of like characterswhich are employed to designate corresponding parts throughout.v4

In Figure 1 is shown a suitable framework I mounted on casters 2. To a sid of the frameendin a suit- In the modification shown in Figure 4, the heads 24 are the full width of the framework. The arms 25 are not, therefore, centrally attached to the heads. This constructionfurnishes' a more concentratedabrasive action over a given area but not aslons a stroke of either brush. It will be understood that the stroke is so adusted that the heads dc not strike one another.

Infeither case, the overall width of the heads is greater than that of the framework so that the heads can be brought close to a wall..

VAlthough specific embodiments of the invention have been illustrated'and described, it will v`be understood that various alterations in the details of construction may be made without departing 'from the scope of the invention as indil cated by the appended claims.

able position as on the top, is mounted a motor 4..'

A countershaft I is Journalled in the frame and carries 9. small pulley 6. The shaft 1 of the mo- What I claim as my invention'is: 1. In an abrasive machine, a portable frame,

a. shaft therein. means for driving said shaft, a

tor carries a small pulley 8 belted at I to a larger pulley III on the shaft l. A- driven shaft II is Joumalled in the frame near the lower end there-4 of and carries a large pulley I2 belted at Il to the small pulley 6. Thus, the speed of the shaft I'I is considerably reduced from that of the'motor shaft 1. Y

At opposite ends of the shaft I I, and preferably outsidecf the frame 2, are mounted disks I4, each carrying a projecting arm I5. To each arm is rotatably-attached a bearing I6, and the bearings are 180 ap'art'with reference to the axis of the shaft Il.

To cach bearing is pair .of arms having crank connections to said shaft at points 180 apart with reference to the axis of said shaft, and abrasive heads rigidly secured tosaid arms and having convexfloor-engaging surfaces, whereby to be rocked by actuation of said crank connections.

2. In an abrasive machine, av portable frame, a

shaft therein, meansffor driving said shaft, a pair of arms having crank connections to saidshaft atpoints apart .with reference to the axis of said shaft, and abrasive heads carried by said arms and having convex door-'engaging surfaces,

whereby to be rocked by actuationof said crank secured a' forwardly extend- 55 connections, each head having substantially half the width of said frame and positioned in endto-end relation to the other, said crank connections having suilicient throw to cause said heads to pass each other.

3. In an abrasive machine, a portable frame, a shaft therein, means for driving said Shaft, a pair of arms having crank connections to said shaft `at points 180 apart with reference to th'e axis of said shaft, and abrasive heads carried by said arms and having convex floor-engaging surfaces, whereby to be rocked by actuation of said crank connections, said heads being substantially as wide as said frame and in end-to-end alinement in the direction of travel.

4.. In an abrasive machine. a portable frame, a shaft therein, means for driving said shaft, a pair of arms having crank connections to said shaft at points 180` apart with reference to the axis of said shaft, and abrasive heads rigidly securedto said arms and having convex floor-engaging surfaces, whereby to be rocked by actuation of said crank connections, the overall width of said heads being slightly greater than that of said frame and symmetrical therewith.

5. In an abrasive machine, a portable frame,

a shaft therein, means for driving said shaft, a pair of arms having crank connections to said shaft at points 180 apart with reference to the axis of said shaft, and abrasive heads carried by said arms and having convex floor-engaging surfaces, whereby to be rocked by actuation of said crank connections, each head having substantially half the width of said frame and positioned in end-to-end relation to the other, said crank connections having sumcient throw to cause said heads to pass each other, the overall width of said heads lbeing slightly greater than that of said frame and symmetrical therewith.

6. In an abrasive machine, a portable frame, a shaft therein, means fordriving said shaft, a pair of arms having crank connections to said shaft at points 180 apart with reference to the axis of said shaft, and abrasive heads carried by said arms and having convex floor-engaging surfaces, whereby to be rocked by lactuation of said crank connections, saidheads being slightly wider than said frame and symmetrical therewith and in end-to-end alinement in the direction of travel.

DAVID PRONOVOST. 

